A building automation system is an arrangement for monitoring, open-loop control and/or closed-loop control of process variables in complex technical systems in a building, or in a campus comprising a number of buildings. A building automation system typically operates heating, ventilation and air-conditioning systems, lighting and shading devices and also access control, security and fire surveillance systems. In the building automation system process variables—such as room air conditioning variables or events for example—are detected, evaluated, monitored, influenced or generated, with the energy consumption of the building or campus also advantageously being optimized by the building automation system.
As a rule the building automation system encompasses and operates a plurality of what are known as field devices, such as sensors and actuators. Examples of typical field devices here are temperature and humidity sensors, air quality sensors, pressure sensors, flow meters, electricity meters, heat meters, brightness sensors, fire alarms, intrusion alarms, alarm or sprinkler devices, drives for hot water valves, thermostat valves, ventilation flaps or blinds, light switches, smart card readers or devices for detecting biometric data. The building automation system typically comprises a plurality of software modules, processes or programs, and in general a number of computers or processors for their activation and also as a rule a plurality of open-loop and closed-loop control devices as well as further devices, for example devices for linking the building automation system to external communication networks, screens of devices for analysis of video signals.
In addition at least an electrical or wireless communication medium is used in a building automation system for the exchange of data of individual devices or parts of systems, as a rule a number of communication networks exist, with cables, optical data communication channels, ultrasound connections, electromagnetic near fields or radio networks able to be used, including fiber optic networks or cellular networks for example. Examples of technologies or standards able to be used for the data exchange are BACnet, LON or LonWorks® from the company ECHELON, the European Installation bus EIB, KONNEX, ZigBee or PROFIBUS defined by German standard DIN 19245.
Building automation systems have been available on the market for more than thirty years. After the general spread of object-oriented programming concepts, building automation systems have also been designed, implemented and offered for more than fifteen years with the aid of object-oriented programming concepts.
Building automation systems with an object-oriented software structure are known for example from WO99/39276A and WO99/60487A.
According to the known related art the addressing of data points of field devices is defined directly in a closed-loop or open-loop control program. Thus BACnet input, output and value objects are typically addressed directly in a program. If a number of identical or similar applications are present in a building automation system, for example a number of room temperature closed-loop control programs, the individual programs must be adapted to the field devices. If the building automation system is to be expanded by further field devices, for example because the room division in the building is to be changed, the program code of the closed-loop and/or open-loop control programs involved is to be adapted accordingly for integration of the additional field devices. Since the program code of a closed-loop or open-loop control program typically has an extremely complex structure, these types of program changes demand people with a soundly-based programming knowledge.